NATURAL SELECTION 101 



Wheti an individual variation which has been lost 

 in a breed that originally possessed it as one of its 

 distinguishing marks reappears after having been lost 

 for a great number of generations, how are we to 

 account for its reappearance ? Why should scientific 

 men be asked to answer such a question ? Such a 

 case can never have occurred within man's knowledge. 

 Such an occurrence, indeed, can never have taken 

 place. 



I shall, however, conceive that it has taken place, 

 and give my answer accordingly. There can be but 

 one way of rationally accounting for it, viz. that 

 it has come direct from Nature's laboratory, as part 

 of the variability of the species. But to his hypo- 

 thetical question Darwin mentions two hypothetical 

 answers, one of which he considers the more probable. 

 The answer which he rejects is that one individual 

 suddenly takes after an ancestor removed by some 

 hundred generations. 



Wherein this answer differs from that which he 

 prefers i cannot conjecture, for they seem identical : 

 unless, indeed, he means that in the former case there 

 is a complete break oil' from the principle of hereditary 

 transmission, as in my explanation of the assumed 

 but impossible fact. But if he means this, the words 

 " takes after an ancestor " ought not to have been 

 used, as the reappearance of the individual variation 

 is due to the variability of the species, and not to 

 the existence of an ancestor who had the same varia- 

 tion. The explanation of the far removed ancestor's 



